Many portable computers, especially hand-held or "palm-top" computers, use integrated circuit memory cards ("IC memory cards") as the primary media of information storage. Such IC memory card include memory storage elements such as static random access memory (SRAM) or such electrical programmable and erasable non-volatile memory elements as "flash" memory. These IC memory cards are typically each the size of a customary credit card. IC memory cards are used in portable computers in place of hard disk drives and floppy disk drives (HDDs, FDDs) in order to achieve the significant advantages of the size, weight, and battery lifetime attributes of the portable computer and to increase portability of the storage media. However, because of the limited memory density attainable in each IC memory card, and the high cost of IC memory chips, using IC memory cards in hand-held computers imposes limitations not encountered in less portable computers, which typically use more power-consuming and heavier hard and floppy disk drives as their primary storage media. Also, in order to avoid the sizes and weights of the necessary power supply unit and the interface adaptor, hand-held computers are typically not equipped with the standardized interfaces (e.g. RS232C) found on larger desktop and laptop computers. This is because standardized interfaces are larger than can be conveniently provided on such hand-held computers and require voltages and power output levels impractical for such hand-held computers, if the requirements of size, weight and long battery lifetime are to be met.
Using IC memory cards as the primary media of storage in these portable computers also creates a problem in software distribution. Since these portable computers find wide applications in the consumer, industrial and vertical markets, an economical way for distributing application software is key to the wide acceptability of these portable computers. Currently, because of the high cost and density limitations, it is neither easy nor economical to sell, distribute or upgrade application software using IC memory cards. An alternative to reduce card cost, rather than using read/write IC memory card, software and data may be distributed using Read-Only Memory (ROM) cards. However, ROM cards require long lead times to produce and require substantial volume to be economical. Since there is seldom guarantee that a given software will sell "well" in volume, a software manufacturer assumes significant inventory risk when adopting a ROM card distribution strategy.
Because portable computers are often issued by corporations to field personnel to provide "at their fingertips" easy access to a large amount of essential information, e.g. product and customer information, there is a need to efficiently distribute and update such information. Currently, such update or distribution to a portable computer user is performed by issuing a new IC memory card with the information already loaded, or by downloading the data or software using a modem. A special modem attachment to a hand-held computer capable of communicating with a facsimile machine, or accessing E-mail or local area networks requires the use of customized software provided on an IC memory card. Such modem attachment is expensive relative to the cost of the hand-held computer, so that many applications of the hand-held computer requiring the use of a modem are rendered uneconomical. As can be readily appreciated from the above, the use of IC memory cards for distribution and update purposes is limited both by the cost and the relatively modest capacity of the IC memory card. Since data transfer using a modem or an IC memory card limits the amount of data that can be transferred at a time, the problem of data distribution is by no means solved by the use of modems or the use of IC memory cards. Further, because prospective users of these portable computers are found in a variety of services, e.g. insurance or property sales, service calls, courier service, field engineering, surveyors, medical calls, accident or property assessors, etc., the use of IC memory cards as the primary storage media in these portable computers is indeed severely limiting the wide spread acceptability in these industries.
Another disadvantage often found in hand-held computers using the IC memory card as the primary storage medium results from the portable computer's inability to provide a variety of system services related to the use of a computer, e.g. connecting to a hard copy device, or transferring important data to a backup facility to prevent loss of data. This is because, as explained above, standardized interfaces to peripheral equipment are typically larger and require generating voltage levels impractical in a hand-held computer, due to their size, weight and power conservation requirements. Thus, each interface to a peripheral device is through a separate adapter which provides both the standard size connector and the necessary voltage level and signal representation conversions. At present, a number of these adapters are required to provide the various interfaces to common peripheral devices. Such adapters are bulky and cannot be simultaneously connected to the single small I/O connector on the hand-held computer. In addition, each adaptor is connected to the hand-held computers via a customized cable and powered by the power supply of the hand-held computer. Even performing the most common applications, such as data backup and printing, require multiple adapters and each adaptor drains the precious battery power from the hand-held computer. To perform data backup, for example, a popular "PC-link cable" is used to connect a hand-held computer to the RS232C (serial) port of a desk top computer over a customized cable and a bulky attachment. The PC link cable provides only data transfer capability and requires both using the customized software and operating the desk top computer. To perform printing, a "printer-link cable" connects the hand-held computer to a printer for printing. Again, the connection to the printer requires another customized cable, a bulky adaptor and uses customized software. Of significance also, because the PC-link and printer-link cables plug into the same port on the hand-held computer, printing and data backup cannot at present be performed simultaneously. Further, since the printer-link and PC-link cables are expensive relative to the cost of the handheld computer, customized cables and adapters are very uneconomical ways to provide common applications in the hand-held computer.
Therefore, because of the limited functionalities necessitated by the size, weight and long battery lifetime requirements of such portable computers, users of these IC memory card-based portable computers are often required to perform through a desk-top computer, such tasks as data backup or printing after the necessary data is transferred to the desk-top computer. The importance of such functions as information backup or obtaining hard copies is self-evident, once one appreciates that the data most often stored in such computers are, for example, telephone numbers, addresses, memoranda, past appointment schedules, spreadsheets or databases etc. Information backups are particularly essential for record keeping and for recovering from an occasional system malfunction.
In addition, because the memory capacity of an IC memory card-based portable computer is limited, it is often necessary to unload the software and data of one application program to create space for use by another application program. Currently, transfer from the portable computer to the desk top computer is cumbersome. For example, the user may be required to buy both a customized connection cable and a special communication software, and be required to perform a sophisticated set of tasks, such as connecting the cable to a RS232C port on the backplane of a desktop computer, setting up files and operating the communication software from the desktop computer. For many people, the apparent level of required skill to perform these tasks form a psychological barrier to their ability to use the portable computer effectively. Further, the cost of a desktop computer is often not justified for people who do not otherwise need a desk-top computer.
In the prior art, a number of computer system of various size, weight, shape, and power supply capabilities can be found. The computer systems described in U.S. Pat. No. 4,330,839 to Miller et. al., entitled "Programmable Calculator including Means for Automatically Processing Information Stored on a Magnetic Record Member", filed on Jun. 29, 1979, issued on May 18, 1982, and in U.S. Pat. No. 4,117,542 to Klausner et. al., entitled "Electronic Pocket Directory", filed on Jul. 7, 1977 and issued on Sep. 26, 1978 are examples of such computers. While each of these patents discloses a computer system comprising a keyboard, a display, electronic circuit boards and a system memory (in the case of Miller et. al., a removable storage medium also), they address neither the problem of limited capacity of an IC memory card nor the attendant high cost of such removable storage medium. Neither do these patents disclose or propose a separate integrated peripheral device to address these deficiencies commonly found in a IC memory card-based portable computer.
U.S. Pat. No. 4,591,974 to Dornbush et. al., entitled "Information Recording and Retrieval System", filed on Jan. 31, 1984 and issued on May 27, 1986, discloses a combination of a hand-held computer and a host computer for generating reports. In this system, the host computer uses data taken in the field by the hand-held unit, which has a keyboard, a display, some memory and a microprocessor. In the system disclosed by Dornbush, essential operations, such as providing forms for data input, providing instructions, and providing codes of authorized users etc., are directed by the host computer, which acts both as an information processing unit and a backup unit to the hand-held computer. Dornbush et al., however, fail to address the problem of transferring large amount of data and software of any type to an IC memory card-based hand-held computers to be stored, reviewed and executed, especially where the hand-held unit has limited capacity in its fixed and removable storage media. Furthermore, Dornbush et al. do not provide a solution to the problems in a portable computer of providing information backup, communicating with other processors, transferring data between removable storage media and obtaining a hard copy of the data without using a host computer.
In the prior art, there are numerous intelligent peripheral devices for such functions as information storage, printout, communication, and input/output (I/O). However, none of these devices integrate these functions into a single device in the manner achieved by the present invention to be described hereinafter.